Fiber optic cable is typically manufactured so as to include an outer buffer coating. The buffer coating is typically a polyamide or other polymer material. The buffer coat, in one aspect, protects the interior of the fiber optic cable from damage while providing a good surface that allows further processing of the cable. The buffer coat also may include additives that provide UV protection to the fiber optic cable.
Further manufacturing steps with fiber optic cable often require a processing of the buffer coat. For example, fiber optic cable may be subject to an inking step. The inking step, which is somewhat similar to wire inking in the semiconductor industry, involves applying a precured adhesive to the exterior surface of the cable. The manufacturing term “inking” is popularly used because of the color of the fluid applied to the cable. Later, the fiber optic cable with the adhesive coat is cured. Upon curing the adhesive bonds the cable into a desired configuration. In one application, inked fiber optic cables are wound and then bound into a spool-like shape. This configuration allows long lengths of fiber optic cable to serve as an interferometer in applications such as a fiber optic gyroscope (FOG).
It has been found that the inking (adhesive application) of fiber optic cable is improved if the cable exterior is first cleaned. While not wishing to be bound to any theory, it is believed that additives in the buffer coat, including UV protective additives, may partially leach out of the buffer coat. This leachant can interfere with the inking process. Previously, a cleaning step was performed by running fiber optic cable through an acetone bath. This kind of procedure is disadvantageous for several reasons. These reasons relate to the nature of acetone which may require certain procedures for safe handling, storage, and disposal. It would be desired to clean fiber optic cable with a process that avoids the use of chemicals such as acetone.
Hence there is a need for a general method to clean fiber optic cable quickly and easily. Further, there is a need for a cleaning method that avoids the use of potentially harmful chemicals. The method should be suitable with existing equipment used in the processing of fiber optic cables. Additionally, the cleaning of fiber optic cable should also allow the application of adhesive to the cable so that the cable may be subsequently cured into a desired configuration. The present invention addresses one or more of these needs.